Hi jomimac,
If you have a fairly recent build, like a 2018 or newer, you might call Heartland Customer Service at 877-262-8032 / 574-262-8030. Ask for the Parts Dep't. Have your VIN # ready. If you're lucky, maybe Heartland is still using that size and design piece of glass. If so, you might be able to order one. Take a clear picture of a cabinet with intact glass along with measurements and be prepared to email them.